Unable to generate Ansible inventory

Hi there,

I've setup a Rundeck host a few months ago. It mainly used for Ansible execution. Today I wanted to execute a Playbook and was faced with an error I don't understand. Originally there were two inventories, one is using the Netbox plugin and the other one is a plane file in ini format. I've deleted the Netbox one in the nodes configuration tab in Rundeck. The other looks like this, just the FQDN:

rundeck.example.org

The issue is, that Rundeck/Ansible is telling me this:

encryptVariable ansible_become_password: [/usr/bin/ansible-vault,
encrypt_string,
--vault-id,
internal-encrypt@/tmp/rundeck/ansible-runner11982000201431882218ansible-script-vault-client.py]
ERROR: encryptFileAnsibleVault:[/usr/bin/ansible-vault,
encrypt_string,
--vault-id,
internal-encrypt@/tmp/rundeck/ansible-runner11982000201431882218ansible-script-vault-client.py]
procArgs: [/usr/bin/ansible-playbook,
gather-hosts.yml,
--vault-id,
internal-encrypt@/tmp/rundeck/ansible-runner11982000201431882218ansible-script-vault-client.py,
--inventory-file=/var/lib/rundeck/inventories/workstations_inventory.ini,
-vvv,
--extra-vars=@/tmp/rundeck/ansible-runner11038963478979370364extra-vars,
--private-key=/tmp/rundeck/ansible-runner42739343837
70840534id_rsa,
--user=rundeck,
--become,
--extra-vars=@/tmp/rundeck/ansible-runner3589667548966691196become-extra-vars,
--become-method=sudo]
ANSIBLE_CONFIG: /etc/ansible/ansible.cfg
[WARNING]: Unable to parse
/var/lib/rundeck/inventories/workstations_inventory.ini as an inventory source
[WARNING]: No inventory was parsed,
only implicit localhost is available
ERROR! Invalid extra vars data supplied. '@/tmp/rundeck/ansible-runner3589667548966691196become-extra-vars' could not be made into a dictionary
ansible-playbook [core 2.16.4]
config file = /etc/ansible/ansible.cfg
configured module search path = ['/var/lib/rundeck/.ansible/plugins/modules',
'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python3/dist-packages/ansible
ansible collection location = /var/lib/rundeck/.ansible/collections:/usr/share/ansible/collections
executable location = /usr/bin/ansible-playbook
python version = 3.10.12 (main,
Nov 20 2023,
15:14:05) [GCC 11.4.0] (/usr/bin/python3)
jinja version = 3.0.3
libyaml = True
Using /etc/ansible/ansible.cfg as config file
host_list declined parsing /var/lib/rundeck/inventories/workstations_inventory.ini as it did not pass its verify_file() method

As far as I understand it, the problem is, that Ansible is putting this --extra-vars=@/tmp/rundeck/ansible-runner3589667548966691196become-extra-vars as an extra variable. But I don't understand where it's coming from.

Can you guys help me figuring out where the hack this is set?